Implement sampling profiler (chromium side change)

base/debug/trace_event_impl.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 
 #ifndef BASE_DEBUG_TRACE_EVENT_IMPL_H_
 #define BASE_DEBUG_TRACE_EVENT_IMPL_H_
 
 #include <stack>
 #include <string>
@@ skipping 618 matching lines @@
       const TraceLog::OutputCallback& flush_output_callback);
   void FinishFlush(int generation);
   void OnFlushTimeout(int generation);
 
   int generation() const {
     return static_cast<int>(subtle::NoBarrier_Load(&generation_));
   }
   bool CheckGeneration(int generation) const {
     return generation == this->generation();
   }
-  int NextGeneration() {
-    return static_cast<int>(subtle::NoBarrier_AtomicIncrement(&generation_, 1));
-  }
+  int NextGeneration();
 
   TimeTicks OffsetNow() const {
     return OffsetTimestamp(TimeTicks::NowFromSystemTraceTime());
   }
   TimeTicks OffsetTimestamp(const TimeTicks& timestamp) const {
     return timestamp - time_offset_;
   }
 
   // This lock protects TraceLog member accesses (except for members protected
   // by thread_info_lock_) from arbitrary threads.
@@ skipping 59 matching lines @@
   scoped_refptr<MessageLoopProxy> flush_message_loop_proxy_;
   subtle::AtomicWord generation_;
 
   DISALLOW_COPY_AND_ASSIGN(TraceLog);
 };
 
 }  // namespace debug
 }  // namespace base
 
 #endif  // BASE_DEBUG_TRACE_EVENT_IMPL_H_